Items considered to be extremely important among items for quality evaluation of fish pastes such as KAMABOKO are whiteness and elasticity.
In preparation of fish pastes excellent in such whiteness and elasticity, it is the quality of Frozen SURIMI that has the most influence on these quality evaluating items, and it is freshness of the fish that has the most influence on the quality.
Almost all fish pastes are now prepared from Frozen SURIMI, and almost all the Frozen SURIMI are prepared from walleye pollacks (gadiformes theragra) as a raw material. Specialization progresses in the industry and manufacturers of Frozen SURIMI and manufacturers preparing fish pastes using it are now present. Most of products which are in circulation between both manufacturers are Frozen SURIMI.
As for the walleye pollacks, it has gradually become difficult to get securely fish meal having a high freshness and a good quality due to recent fishing spots having become distant, delay of time from harvest to processing following decrease of fishery amount in one's country and purchase from abroad, and further decrease of fish source, etc.
That is, preparation of Frozen SURIMI having a good quality has become difficult due to the fact that every time fish meat is obtained scattering of its freshness has become larger and that fishery amount has been decreased.
Further, fishery term of walleye pollacks are limited to relatively short term and on the other hand, preparation of fish pastes is carried out throughout the year. Thus, Frozen SURIMI is preserved in a frozen state, when preserved for a long term, over a long term of nearly one year, and denaturing of fish meat proteins in the frozen state could occur in the preservation.
It is lowering of whiteness and elasticity of fish pastes that has been brought about from these background, and in order to solve these problems, several methods have been proposed, and as for improvement of whiteness many potential inventions have been introduced.
Many of these methods have been introduced as those of improving the whiteness as well as preventing lowering of the elasticity or increasing the elasticity.
It is, for example, a method of using surfactant(s) such as glycerine monofatty acid ester together with sugar(s) and/or sugar alcohol(s) for filtrated meat obtained by a conventional method that has been proposed as a method for improving the whiteness and elasticity.
On the other hand, many methods for improving only the elasticity have been proposed, and examples thereof include a method of adding 0.5 to 5 weight parts of plasma protein or the white of eggs per 100 parts of the meat, and the like.
However, in any of the introduced methods for improving lowering of the elasticity together with enhancing the whiteness, the effect is weak. By the reason and other reasons, although there are methods which satisfactorily improve the whiteness, there are scarcely methods which satisfactorily improve the elasticity.
Further, even the methods which have been introduced as those of improving only the elasticity have not been satisfactory ones because when the improvers used therein are added in an amount enough to exhibit a satisfactory improvement effect, there arises a fatal problem in taste, aroma, etc.
For example, plasma proteins have an animal odor and an bloody odor peculiar to blood, and terribly impair the flavor of KAMABOKO, and the white, which exhibits its elasticity increasing effect for the first time when used in much amount, has a strong trend to harden the products and a disadvantage to leave a smell peculiar to the white.
It is generally jelly strength that is used as an index of the elasticity, and jelly strength is calculated as the product of W-value (namely, fracture strength or hardness) and L-value (namely, dent or flexibility). Methods which have hitherto been introduced scarcely increase both values or increase W-value alone.
That is, although there have been methods to increase hardness of fish pastes, there has been no method to increase flexibility, i.e. L-value, and improvement in this point has strongly been desired.